/* SPDX-License-Identifier: GPL-3.0-only */
/*
 * Native ESP-IDF Wi-Fi configuration and persistence.
 *
 * The public structures below are also the version-1 NVS wire format. Keep
 * every field fixed-width and introduce a new schema version for layout
 * changes; do not silently reinterpret an existing blob.
 */

#pragma once

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#include "esp_err.h"

#define WIFI_CONFIG_SCHEMA_VERSION 1U
#define WIFI_CONFIG_BLOB_SIZE 528U
#define WIFI_CONFIG_STA_PROFILE_BLOB_SIZE 104U

#define WIFI_CONFIG_NVS_NAMESPACE "wifi_app"
#define WIFI_CONFIG_NVS_BLOB_KEY "config"

#define WIFI_CONFIG_STA_PROFILE_COUNT 4U
#define WIFI_CONFIG_SSID_MAX_LEN 32U
#define WIFI_CONFIG_PSK_MIN_LEN 8U
#define WIFI_CONFIG_PSK_MAX_LEN 63U
#define WIFI_CONFIG_DEFAULT_AP_PSK_LEN 16U
#define WIFI_CONFIG_AP_CHANNEL_MIN 1U
#define WIFI_CONFIG_AP_CHANNEL_MAX 11U

/* uint8_t aliases keep the persisted representation independent of enum size. */
typedef uint8_t wifi_config_ap_policy_t;
enum {
    WIFI_CONFIG_AP_POLICY_OFF = 0U,
    WIFI_CONFIG_AP_POLICY_FALLBACK = 1U,
    WIFI_CONFIG_AP_POLICY_ALWAYS = 2U,
};

typedef uint8_t wifi_config_security_t;
enum {
    /* ESP-IDF thresholds can express WPA2-or-stronger, not WPA2-only. */
    WIFI_CONFIG_SECURITY_MIXED = 0U,
    WIFI_CONFIG_SECURITY_WPA3 = 1U,
};

typedef uint8_t wifi_config_load_source_t;
enum {
    WIFI_CONFIG_LOAD_GENERATED_MISSING = 0U,
    WIFI_CONFIG_LOAD_STORED = 1U,
    WIFI_CONFIG_LOAD_GENERATED_INVALID = 2U,
};

typedef struct {
    /* Persisted booleans use 0/1 bytes so the blob layout remains fixed. */
    uint8_t enabled;
    uint8_t priority;
    wifi_config_security_t security;
    uint8_t ssid_len;
    uint8_t psk_len;
    uint8_t reserved[3];

    /* Lengths are authoritative; these fixed-width byte arrays need no NUL. */
    uint8_t ssid[WIFI_CONFIG_SSID_MAX_LEN];
    uint8_t psk[WIFI_CONFIG_PSK_MAX_LEN];
    uint8_t reserved_tail[1];
} wifi_config_sta_profile_t;

typedef struct {
    uint32_t schema_version;
    uint16_t blob_size;
    uint8_t enabled_at_boot;
    wifi_config_ap_policy_t ap_policy;
    uint8_t ap_ssid_len;
    uint8_t ap_psk_len;
    uint8_t ap_channel;
    uint8_t reserved[5];

    uint8_t ap_ssid[WIFI_CONFIG_SSID_MAX_LEN];
    uint8_t ap_psk[WIFI_CONFIG_PSK_MAX_LEN];
    uint8_t reserved_tail[1];

    wifi_config_sta_profile_t profiles[WIFI_CONFIG_STA_PROFILE_COUNT];
} wifi_app_config_t;


/* Generates a unique AP SSID and a fresh random AP password. */
esp_err_t wifi_config_defaults(wifi_app_config_t *config);
esp_err_t wifi_config_validate(const wifi_app_config_t *config);

bool wifi_config_parse_ap_policy(const char *text, wifi_config_ap_policy_t *value);
const char *wifi_config_ap_policy_to_string(wifi_config_ap_policy_t value);
bool wifi_config_parse_security(const char *text, wifi_config_security_t *value);
const char *wifi_config_security_to_string(wifi_config_security_t value);

/*
 * Storage uses only wifi_app/config. Invalid, stale, or absent blobs are left
 * untouched. source distinguishes first boot from incompatible stored data so
 * callers never overwrite a potentially migratable schema automatically.
 */
esp_err_t wifi_config_storage_init(void);
esp_err_t wifi_config_load(wifi_app_config_t *config,
                           wifi_config_load_source_t *source);
esp_err_t wifi_config_save(const wifi_app_config_t *config);

/* Pass NULL to generate fresh defaults, or supply validated defaults to save. */
esp_err_t wifi_config_reset_storage(const wifi_app_config_t *defaults);

/* Compatibility wrapper around the shared secure_wipe() implementation. */
void wifi_config_secure_wipe(void *data, size_t size);